Textbook Question
Kornberg showed that nucleotides are added to the 3' end of each growing DNA strand. In what way does an exposed 3'-OH group participate in strand elongation?
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Ch. 11 - DNA Replication and Recombination
Klug12th EditionConcepts of Genetics ISBN: 9780135564776
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Table of contents
- Ch. 1 - Introduction to Genetics17
- Ch. 2 - Mitosis and Meiosis36
- Ch. 3 - Mendelian Genetics51
- Ch. 4 - Extensions of Mendelian Genetics74
- Ch. 5 - Chromosome Mapping in Eukaryotes51
- Ch. 6 - Genetic Analysis and Mapping in Bacteria and Bacteriophages46
- Ch. 7 - Sex Determination and Sex Chromosomes33
- Ch. 8 - Chromosome Mutations: Variation in Number and Arrangement40
- Ch. 9 - Extranuclear Inheritance31
- Ch. 10 - DNA Structure and Analysis43
- Ch. 11 - DNA Replication and Recombination44
- Ch. 12 - DNA Organization in Chromosomes30
- Ch. 13 - The Genetic Code and Transcription54
- Ch. 14 - Translation and Proteins47
- Ch. 15 - Gene Mutation, DNA Repair, and Transposition41
- Ch. 16 - Regulation of Gene Expression in Bacteria29
- Ch. 17 - Transcriptional Regulation in Eukaryotes41
- Ch. 18 - Post-transcriptional Regulation in Eukaryotes33
- Ch. 19 - Epigenetics33
- Ch. 20 - Recombinant DNA Technology44
- Ch. 21 - Genomic Analysis36
- Ch. 22 - Applications of Genetic Engineering and Biotechnology36
- Ch. 23 - Developmental Genetics37
- Ch. 24 - Cancer Genetics34
- Ch. 25 - Quantitative Genetics and Multifactorial Traits54
- Ch. 26 - Population and Evolutionary Genetics45
Chapter 11, Problem 12
Summarize and compare the properties of DNA polymerase I, II, and III.
Verified step by step guidance1
Start by identifying the primary function of each DNA polymerase enzyme in prokaryotes, focusing on DNA polymerase I, II, and III.
Describe DNA polymerase I, emphasizing its role in removing RNA primers through its 5' to 3' exonuclease activity and filling in the resulting gaps with DNA.
Explain DNA polymerase II, noting its function mainly in DNA repair and its 3' to 5' exonuclease proofreading activity to maintain DNA fidelity.
Detail DNA polymerase III as the main enzyme responsible for the bulk of DNA synthesis during replication, highlighting its high processivity and 3' to 5' exonuclease proofreading activity.
Compare the enzymes by summarizing their exonuclease activities, roles in replication versus repair, and their relative importance in the DNA replication process.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
DNA Polymerase I
DNA Polymerase I is primarily involved in DNA repair and the removal of RNA primers during replication. It has 5' to 3' polymerase activity, 3' to 5' exonuclease proofreading, and unique 5' to 3' exonuclease activity that removes RNA primers, allowing replacement with DNA.
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DNA Polymerase II
DNA Polymerase II functions mainly in DNA repair and replication restart after damage. It possesses 5' to 3' polymerase and 3' to 5' exonuclease proofreading activities but lacks 5' to 3' exonuclease activity, making it less involved in primer removal.
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DNA Polymerase III
DNA Polymerase III is the primary enzyme responsible for bacterial DNA replication. It has high processivity and 5' to 3' polymerase activity, along with 3' to 5' exonuclease proofreading, but lacks 5' to 3' exonuclease activity, so it cannot remove RNA primers.
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Related Practice
Textbook Question
List and describe the function of the ten subunits constituting DNA polymerase III. Distinguish between the holoenzyme and the core enzyme.
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Textbook Question
Which characteristics of DNA polymerase I raised doubts that its in vivo function is the synthesis of DNA leading to complete replication?
Textbook Question
List the proteins that unwind DNA during in vivo DNA synthesis. How do they function?
Textbook Question
What was the significance of the polA1 mutation?
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Textbook Question
Distinguish between
(a) unidirectional and bidirectional synthesis, and
(b) continuous and discontinuous synthesis of DNA.